CustomerTable to be tested

<?php
namespace Customer\Table;

use Customer\Entity\CustomerEntity;
use Customer\Hydrator\CustomerHydrator;
use Zend\Db\Adapter\AdapterInterface;
use Zend\Db\ResultSet\HydratingResultSet;
use Zend\Db\TableGateway\TableGateway;

class CustomerTable extends TableGateway
{
    public function __construct(AdapterInterface $adapter)
    {
        $resultSetPrototype = new HydratingResultSet(
            new CustomerHydrator(),
            new CustomerEntity()
        );

        parent::__construct('customers', $adapter, null, $resultSetPrototype);
    }

    public function fetchList()
    {
        $select = $this->getSql()->select();

        return $this->selectWith($select);
    }
}